1. Field of the Invention
The present disclosure relates to fire detectors, and more particularly to fire detectors used to indicate an overheat or fire condition.
2. Description of Related Art
Linear pneumatic fire detectors are used in commercial aerospace to detect engine and auxiliary power generators from fire and overheat events. These detectors are also used in similar applications for land/sea vehicles and some fixed based power plants. Some of the most common fire detector types are discrete thermocouple, continuous linear thermocouple, continuous linear thermistor wire, and pneumatic gas expansion. The pneumatic gas expansion type detectors function on the principle that an inert gas within the sensor tube expands to close a contact switch and annunciate an alarm condition. When the gas cools the sensor resets.
The pressurized background gas expands in accordance to the physical gas laws. One of the ends of the pneumatic detectors is incorporated into a housing that comprises an alarm and fault integrity. When the sensor tube portion of the pneumatic detector in its final form is exposed to high temperature, the pressure inside will rise. Once the pressure reaches a predetermined threshold an alarm will initiate indicating a hazardous situation (i.e. a fire). A drawback to the current pneumatic detectors is that they only function in three discrete states; normal, alarm, or fault. The current pneumatic detectors typically have two internal pressure switches, one that reports the static no alarm (normal or fault) pressure state and a second switch that reports the alarm pressure state.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved pneumatic fire detector with trend monitoring. The present disclosure provides a solution for this need.